Abstract: As one of the main technologies in CCUs process,chemical absorption technologies have been widely used in CO_2 capture and purification process. However,traditional industrial MEA solution as absorbent has many disadvantages,such as high energy consumption,strong corrosion and degeneration. Therefore,the development of a new generation of composite amine absorbent has become the focus of current research. In this study,based on the sterically hindered amine 2-amino-2-methyl-1-propanol( AMP),a series of TETA/AMP composite water-based absorbents were synthesized for CO_2 capture in flue gas. Through the comparison test of absorption-desorption performance of solutions with different ratios,the absorption capacity,absorption rate,regeneration rate and other factors were comprehensively investigated,and finally the best ratio was obtained. And it is found that the TETA/AMP composite absorption liquid with a mass ratio of 1: 1 has the best absorption and desorption performance. Compared with pure AMP,its saturated absorption capacity is nearly doubled,and the maximum regeneration rate can reach 0.03 g/min. In the process of CO_2 absorption by the composite absorbent,the sterically hindered amine AMP with a faster absorption rate can quickly capture and activate CO_2 molecules,and then it is transfered to the alkenylamine TETA with multiple reaction sites for storage. In the desorption process,due to the steric hindrance effect of AMP,the connection with CO_2 molecules is easier to be broken,thereby increasing the regeneration rate. At the same time,quantum chemical calculations are used to simulate the monomers and compound unit,so as to deduce the formation process of the compound system. In this work,the relationship between the distribution of the electrostatic potential on the molecular surface and the monomers forming the compound system was discovered,the role of different functional groups in the formation of the compound system was analyzed,and the necessity of the hydroxyl group in the formation of the compound system was proposed.